There is a small hole on the outer side of the bottle for saving inner material to be spoilt from hot water, leak proof.

MULTIPLE USES - This Pure Copper Drinking and Water Storing Pot Keeps All Your Favorite Drinks Cold and Refreshing; Used for Water Drinking Copper Infused Water, Iced Coffee, Iced Tea, or any Whiskey, Vodka, Rum, and Tequila Mixed Drinks; Freezeable; Leave in the Freezer for a Frosted Glass Effect and Keep Your Drink Colder Much Longer; This Glass is Heat Sensitive; Let Hot Drinks such as Coffee or Tea Cool Prior to Use as Handle and Glass Will be Hot.